Title

Authors

Document Type

Technical Report

Publication Date

6-1-1991

Keywords

Aquatic macroinvertebrates, National Wildlife Refuge, Arkansas

Abstract

The primary purpose of this study was to survey the diversity of the aquatic macroinvertebrates of the White River National Wildlife Refuge (WRNWR). Determining relative abundance and distributional and seasonal patterns were secondary objectives. No comprehensive investigations of the WRNWR aquatic macroinvertebrates had been conducted previously, and it was hypothesized that this relatively undisturbed area may serve as a refugium. Further, this study provides base line data by which management programs can be composed. Thirty sampling stations were established within the WRNWR. Samples were collected from north to south at a basic rate of five stations per month. Revisit collections were made during the subsequent six month period, providing a total of 60 samples. Each station was sampled on each occasion for 1.4 man hours with a Turtox Indestructible dip net, and specimens were preserved in 70% ethanol. Three black light samples were taken to augment the species list. Of the 15,083 organisms collected, 80.4% were insects while 6.4% were decapod crustaceans, 5.2% were molluscs, 4.5% were isopods and 2.1% were amphipods. Number of taxa collected per station ranged from 8-36, while numerical standing crop ranged from 8-600. Shannon-Wiener diversity values ranged from 1.056-4.717. The most complex aquatic macroinvertebrate communities were found, in general, in the southeastern portion of the refuge. Great diversity here and at a few other stations was correlated with minimal disturbance by human activity. Parts of the WRNWR apparently function as a refugium. Four of the ten leach species collected, and an uncommon beetle, Suphis, were new state records.